Detective Superintendent Ailsa Kent, of Thames Valley Major Crime Unit, told reporters: “The cause of death is consistent with our current belief that Andrew was caught between a vehicle and the road and then dragged for a distance.”

Det Sup Kent said it remains unclear how PC Harper “came to be out of his vehicle and then caught under the suspect vehicle”.

She said: “What we do know is that Andrew and his crewmate were attending a reported burglary in Bradfield Southend.

“While responding, the officers located a vehicle that was suspected to be involved in the burglary, in Lambdens Hill.”

Officers have been granted permission to keep the group – boys and men aged between 13 and 30 – in custody for a further 36 hours.

The caravan and mobile home site near Bughfield Common is a run by the local authority, police said.

Image:Ten people were arrested at a local caravan and mobile home park

Image:PC Harper’s police colleagues placed flowers near where he died

PC Harper was a member of the Roads Policing Proactive Unit based at Abingdon police station.

He was also a newlywed, having married in Oxfordshire last month, and was due to go on his honeymoon with wife Lissie next week.

Earlier on Saturday PC Harper’s father Philip told Sky News that the family were “devastated”, adding: “we’re in a bad place”.

Meanwhile, Det Sup Kent thanked residents nearby for their patience and cooperation during the police investigation.

She also thanked the public and wider police family “for their messages of support during this extremely difficult time for everybody affected by Andrew’s death”.